Using a variable as array name

Question

I have a data structure like so:

var questions {
  'foo' : [
    {
      'question' : 'Where do babies come from?',
      'choice' : [ 'a', 'b', 'c', 'd' ]
    },
    {
      'question' : 'What is the meaning of life?',
      'choice' : [ 'a', 'b', 'c', 'd' ]
    }
  ],
  'bar' : [
    {
      'question' : 'Where do babies come from?',
      'choice' : [ 'a', 'b', 'c', 'd' ]
    },
    {
      'question' : 'What is the meaning of life?',
      'choice' : [ 'a', 'b', 'c', 'd' ]
    }
  ]
}

I need to navigate and select various data contextually. I need bar and 1 in questions.bar[1].question to be variable. I have written the following and have had no success:

var quiz = $('[id*="Quiz"]');
var skill = quiz.attr('id').substring(0, 3); // 'foo' or 'bar'
var string = '';

for(var i = 0; i < questions[skill].length; i++) {

  var baz = skill + '[' + i + ']'; // need to produce 'foo[0]' or 'bar[0]'

  string += (
    '<div>' +
    '<p>' + questions[baz].question + '</p>' // need to select questions.foo[0].question or questions.bar[0] and then print '<p>Where do babies come from?</p>'
  );
}

If anyone knows how to make the array name itself a variable, that would be much appreciated.

questions[skill].length need to be questions.skill.length (if you are sure that skill is coming as foo or bar) — Death-is-the-real-truth
– Death-is-the-real-truth, Commented Jan 15, 2018 at 5:18
@AlivetoDie that doesn't look right at all. There is no skill property — Phil
– Phil, Commented Jan 15, 2018 at 5:20
@phil in his code he created that variable and writen there that it's coming like foo or bar — Death-is-the-real-truth
– Death-is-the-real-truth, Commented Jan 15, 2018 at 5:21
@AlivetoDie yes, but questions.skill is undefined. The correct code is questions[skill].length — Phil
– Phil, Commented Jan 15, 2018 at 5:22

treyhakanson · Accepted Answer · 2018-01-15 05:18:51Z

7

The following should do the trick; you just need to pull the array value as you normally would:

var baz = questions[skill][i]; // will be `foo[i]` or `bar[i]`

This works because questions[skill] is a reference to the array, whose elements can then be accessed as usual. So then you would simply do the following to pull the question text:

'<p>' + baz.question + '</p>'

answered Jan 15, 2018 at 5:18

treyhakanson

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